Abstract: A string tensioning device for a racquet stringing machine. The device includes a stallable electric motor for providing torque to a tensioning shaft and an electric control circuit for regulating the torque provided by the motor. A manual adjustor is provided to adjust the torque to a preselected desired torque. A gripper is located on the tensioning shaft for gripping the string to be tensioned. In use the motor stalls at a preselected torque permitting the string to be tensioned a predetermined amount.

Abstract: A pressure vessel having a removable lid for storing objects under pressure is disclosed. The pressure vessel includes a pressure chamber having a smooth walled opening of uniform size against which the removable lid seals with an interference fit. A stop is secured to the pressure vessel and restrains one end of the removable lid from sliding along the smooth wall. At the other end of the lid there is pivotally mounted a locking member which engages under a locking projection fixed to the pressure vessel. A lever arm, pivotally attached to the locking member, uses a levering projection (fixed to the pressure vessel) as a fulcrum to assist in fitting the lid to and removing the lid from the pressure vessel. The pressure vessel is provided with a valve for manually dumping pressure from the pressure chamber and is also provided with a source of pressurized fluid for pressurizing the chamber to a predetermined amount of pressure.